This proposal describes an immuno-epidemiologic study of occupational asthma and hypersensitivity among women employed in the blue crab processing industry in North Carolina. By the nature of their work, crab pickers are unavoidably exposed to atomized particles of crab shell, meat and fluids, all of which have been shown in clinical studies to be allergenic. Previous occupational studies have implicated shellfish and crustacea (other crab species) in producing an allergic asthmatic response in hypersensitive individuals; however, no study has investigated the association between asthma and occupational exposure to the blue crab, Callinectes sapidus. The specific aims of this study are as follows: to estimate the prevalence of occupational asthma among black women employed in North Carolina as crab pickers; to document a possible outward worker migration related to hypersensitivity to crab and subsequent respiratory symptoms; and to describe differences in demographic characteristics between pickers leaving the workforce and those remaining, by symptom and sensitivity status. The cohort of crab pickers in North Carolina will be enumerated in 1985 using plant records and rosters, and followed through 1988 for employment status. This will allow estimation of employee turnover rates and will identify current versus former workers. Random samples of 175 current and 175 former employees will be interviewed for information on health history (especially allergic symptoms), employment history and other socio-demographic variables, and skin scratch tested for reactivity to crab antigen as well as three common environmental allergens. These groups will be compared in the analysis on history of asthmatic symptoms and on skin test results, controlling for confounders. It is hypothesized that a greater proportion of former employees will demonstrate a positive skin reaction toward crab antigen and history of symptoms than their counterparts remaining in the industry.